RepEvox

iTrader: (14)

It looks like a lower case 'm' which would be milli (1/1000). Mega ohms would be 'M'

I never knew lipos were that sensitive to temperature. It would seem their operating temperature is pretty small. Luckily I live in California where it's 50-70 outside most of the year so I almost never worry about cold/heat.

Edit: here's some interesting information that confirms the other info in this thread

spookie

iTrader: (25)

Great find! The article is discussing milliohm.

Herrsavage

Couple of lipo-related gearing questions.

I've been watching a lot of vids recently of Kratons etc.. running on 6S - something I've never done. Over two years ago I bought a 5S lipo, and have never used it at all. So I'm starting to wonder about the possibilities for my three brushless RC's - an MT4 G3(currently with a 15t pinion I think, and bald truggy tires..), converted Tamiya TRF801XT, and the SC8e.

I think for starters I want to try 5S in the Tamiya. It currently has the ESC and motor out of an MT4 G3 (HW 150 and Ripper 2000), a 14t pinion, and MT4 G3 monster truck tires on it. Do I have to change the gearing?(I don't want to..) Next, what exactly do I have to program on the programmer board thing for the LVC, and how? I'm paranoid about messing with that cuz it went off full throttle once when I was messing with it and took a chunk of my thumb with it..

Next, the SC8e is stock, which afaik means nothing higher than 4S. It is completely boring on 4S though, so it definitely needs a boost. It's the old original SC8e with the Castle 2200 and the mini Monster ESC thing. I would consider getting a new ESC, but I do not want to have to solder anything. Is that possible?

Would it be better to invest in a bunch of 3s batteries for running on 6s, or should I settle on 5s for all of them(then, 5s or 3s + 2s?)? I want whichever is cheaper and at the same time low maintenance.. I.e. I don't want to have to be paranoid all the time that on 6s it will go up in flames. Back in the day I saw several videos of MT4 G3's doing exactly that - and on 5S.. I don't know if it was because they were run in hot temps, or overgeared, or what. I remember one in particular on a basketball court which was with a 14t pinion on 5s only, and it went up in flames. It was somewhere hot and humid though.. Anyway, that's something I really want to avoid.

Thanks..

Herrsavage

To the point.. Can someone recommend the cheapest and simplest way possible to get more speed out of my SC8e? It's stock with the MMP ESC and Castle 2200 motor... It's boring on 4S. But with the stock ESC you can't run more than 4S afaik. Thanks..

0verkill

iTrader: (8)

I would get a single 6S battery over two 3S batteries in series. It's just simpler, more efficient, less wire mess, etc. With 6S you need a lower kv motor like 1500kv for example. This is a good 6S battery for cheap - http://www.hobbyking.com/hobbyking/s...Lipo_Pack.html. Changing the LVC is very simple with Castle ESC's, I have mine set to 3.5v and it works great. I can't comment on the HW stuff. Any new ESC you get will require soldering your choice of connector on it. The Mamba Max Pro 1/10 ESC is rated for 6S. The only way to get more speed is to up the voltage or up the gearing. A larger pinion and/or smaller spur are cheap. Just keep on eye on the temps, it would be ideal to keep the motor under 160*.

Herrsavage

I tried different pinions. It was bogging with a 19t... 18 seems max on 4S.

Overdriven

iTrader: (18)

Increasing voltage does two things. It increases the amount of power the motor makes and increases rpm. If you adjust the gearing to maintain the same top speed (negating the increased motor rpm) the load on the motor remains the same, which means the wattage the motor draws is (more or less) the same. Since watts = volts times amps, more voltage means less amps. But since we have a bit more power we can increase the top speed a little too and that's what I've done in my recommendations below.

For the 801xt you might be able to get away with dropping a 5s in it and not touch a thing. It depends on how much the tires balloon. The calc says you're around 40mph now on 4s, 5s will be about 50mph. I don't know how good that Ripper motor is (the HW 150 esc will be fine either way) but if you want to be on the cautious side drop it to 13/50 to bring it down around 45mph. On 5s with 13/50 you'll have a nice boost in power, some extra top speed and everything should be safe but always monitor temps anyway. If I had to guess 14/50 might be pushing it for the Ripper motor, requiring a heatsink/fan to keep temps in check.

The MMP is rated to 6s but it does have a lower amp rating than a MMM. That just means you should be a little more careful with gearing and monitor temps. You can find esc's with battery connectors already soldered if you'd rather replace it but they're not all that plentiful and may not be in a configuration (2 batteries instead of 1 or vice versa) you want. If you go 5s with the MMP I'd drop it down to 16/46 (43ish mph) for a safe baseline to see how temps are and gear up from there. Even at 16/46 on 5s you're still going to be faster than 18/46 on 4s and have more power to boot.

The MT4 G3, I'm not touching. There's tons of info on wonder tiger about those on all different voltages and I really don't feel like looking up gear ratios for it.

Herrsavage

Thanks.. I think at this stage I'm more or less fine with the Tamiya and MT4 G3 on 4S. The SC8e though needs a big increaes in speed to keep my attention. So it needs to be set up for 50mph or so.

Also, I would just test the 5s in the Tamiya, but then I need to reprogram the ESC for the LVC right? That's kind of a pain - especially if you have to take the tires off. If I were to do that, do people switch back to 4s without reprogramming the LVC, and just keep an eye on it, or is that just not done?

Lastly, would near freezing outdoor temps make it safer to try 5s in the SC8e as is - i.e. 18/46? Or should I forget that? (Though I am lazy, I do want to avoid explosions..)

Overdriven

iTrader: (18)

Herr I think you're getting lazy in your old age, can't solder, can't take the tires or pinion off as a precaution when programming? What happened to the guy who'd tune the clutch springs and such? Lol. I'm busting on ya.

The Hobbywing and Castle allow you to set the cutoff voltage per cell, that's obvious. But each also have another parameter for the number of cells. This can be set for a specific number of cells or the esc can auto detect the number of cells. Castle esc's are set for auto detect by default, you can verify by listening to the number of tones as it counts off during initialization. The MMP actually won't initialize if there's a conflict and it's super easy to set with the Castle link. The HW I have no idea what's the default or what TT may have specified as the default. Break out the manual, remove the tire or pinion, (make sure it's) set it to auto detect so you don't have to worry about it and switch between 4s and 5s to your hearts content.

As for the cold. Yes it will definitely help and I'd think everything would be fine as on the SC8 with 5s. But come on Herr it's just a pinion not a diff, unless you don't have one on hand. The motor isn't a concern, it should be able to handle that gearing even in warmer temps. My concern is the MMP esc, which I've never used and do t read about too much in 1/8. But with its thermal protection, the cold and some temp monitoring I wouldn't worry about it failing. As the weather warms I'd definitely keep more of an eye on it.

Herrsavage

Thanks. I thought the whole point of electric was less maintenance.. No clutch, air filter, starter box, etc. (So far that's true btw - on 4S.. I don't do jack to them, no temp reading, nothing.. And all good..)

I'm really only concerned about the SC8e right now, because it's really just lame on 4s. I might try just putting in the 5s and see what happens. Don't have a Castle link though and not buying one..

It's been a while since I read about it, but I think with the HW you have to "trick" it to run 5s, by lowering the LVC to 2.8 or something.. Bug again, I'm not too worried about doing that just now.

And yeah, OK, jus removing the pinion is no prob.. Though it does suck somewhat I guess if you want to run right away, as the threadlock isn't dry..

One more question - does the Castle 2200 an oddball wiring? What exactly do you have to do to run that motor with a HW 150 ESC? The wires are totally different thicknesses et..

Thanks for the help!

ps Just got the 5S Lipo (XCell 5S 4200 35C) out of the cellar, where it's been sitting unused for nearly two years(or is it three now?..) All cells were right at about 3.8, except the second, which was 4.16...

Overdriven

iTrader: (18)

There really isn't much maintenance or wrenching or anything involved with electric once it's setup. I setup my XXLe and have barely touched it in years besides the annual winter tear down for cleaning, inspection and lube. I only temp it the first run of the season and maybe on really hot days just for my piece of mind. But you're talking about modifying the setup, get it figured out and you can go back to basically not touching anything.

Well testing the MMP to see if it's on auto detect is as simple as plugging in the 5s. It should do its chime, then 5 beeps counting off the cells followed by the chime again. If it doesn't do all that then you need to change the settings. You're not going to hurt it by plugging in the 5s. It's a royal pain in the neck but I believe you can change the cell count to auto detect by programming with the transmitter. Don't ask me how, I read about it but I never attempted.

I have no idea what size the connectors or anything is on the HW. The Castle 2200kv motor wires have 6.5mm bullets on them. Soldering is going to be required to connect the two, personally I'd remove the bullets on the esc and solder Castle 6.5mm bullets on it. Trying to get the thicker gauge Castle wires in a smaller HW bullet may not be possible.